6. The graph shows the relative costs of three sources of drinkable water from 1970 to 2020 (projected): piping in freshwater from farther than 75 miles away, piping in freshwater from less than 75 miles away, and treating brackish (non-drinkable) groundwater. Based on the information contained in this graph alone, which one of the following statements can be determined or reasonably inferred?
Answer: A
In 2005, the cost of treating brackish groundwater was about the same as the cost of piping in freshwater from less than 75 miles away.
In 2005, the graph indicates that the costs of treating brackish groundwater and piping in freshwater from less than 75 miles away were comparable, allowing this statement to be reasonably inferred.
A) In 2005, the cost of treating brackish groundwater was about the same as the cost of piping in freshwater from less than 75 miles away.
This option is correct because the graph shows that in 2005, the costs for both options were nearly equal. This direct comparison is supported by the visual data provided in the graph.
B) Treating brackish groundwater to obtain freshwater has declined in popularity since 1970.
This option is incorrect as the graph does not provide any information regarding the popularity of treating brackish groundwater. It solely illustrates cost trends, not consumption or usage rates.
C) After 2020, it will be necessary to pipe in freshwater from greater and greater distances.
This statement cannot be determined from the graph, as it only projects costs up to 2020 without indicating future trends beyond that year. There is no evidence in the data to support this inference.
D) In the year 2000, it cost less to treat brackish groundwater than to pipe in freshwater from more than 75 miles away.
This option is incorrect because the graph must be analyzed for specific cost comparisons in the year 2000. Without the exact data points, this statement cannot be confirmed or denied.
E) Since 1970, the cost of piping in freshwater has increased slowly but steadily.
While this may seem plausible, the graph does not explicitly confirm a steady increase in costs for piping freshwater since 1970, making this statement speculative rather than definitive.
Conclusion
Option A is the only statement that can be accurately confirmed based on the graph's data, highlighting a specific cost comparison for the year 2005. All other options either lack sufficient data for validation or cannot be reasonably inferred from the presented information, demonstrating the importance of precise interpretation of graphical data.